378 research outputs found
Identifying Galaxy Mergers with Quantitative Morphological Parameters in Simulated James Webb Space Telescope Images
Mergers play an important role in the formation and evolution of galaxies by triggering starbursts, AGN activity, and morphological transitions from disks to ellipticals. They can also cause morphological disturbances in a galaxy’s appearance, such as double nuclei, tidal tails, and other asymmetries, which can appear before or after a merger has occurred. Therefore, one way to identify low redshift galaxy mergers is to search for these morphological signatures via quantitative morphological parameters, which quantify a galaxy’s light distribution (such as Sérsic profiles, or the CAS system, G and M20, and the MID statistics). However, for high redshift galaxies, these parameters can be affected by biases due to poor resolution and noisy images. The upcoming James Webb Space Telescope (JWST) will be able to probe higher redshifts than ever before for morphological studies with high spatial resolution. The Cosmic Evolution Early Release Science (CEERS) Survey will use JWST’s near-infrared camera to reveal detailed galaxy morphologies over a wide range of redshifts. In preparation for CEERS images, this works seeks to understand how well those common morphological statistics will be able to identify JWST mergers.
Multiwavelength SĂ©rsic profile fitting program Galapagos-2 and the nonparametric morphology program statmorph were run on simulated JWST images from Illustris, which were modified to match the specifications of CEERS imaging. Using Illustris merger history catalogs, plots of different combinations of the rest-frame morphologies of the simulated galaxies, binned by redshift, were made as functions of merger timescales. These plots do not separate mergers from non-mergers as cleanly as previous studies have found, regardless of redshift or merger timescale. This indicates that a more sophisticated analysis method, such as principal component analysis, will be required in order to effectively isolate JWST mergers from other galaxies
Chemical Functionalization of thiol-acrylate polyHIPEs
The work described herein describes the synthesis and subsequent functionalization of thiol-acrylate emulsion templated porous polymers (polyHIPEs). Thiol-ene “click” chemistry has been employed in order to produce polyHIPEs from multifunctional thiol and acrylate monomers, and the level of residual thiol within the material determined. These residual thiols have then been used as “reactive handles” which allow for the functionalization of the thiol-acrylate polyHIPE post-polymerization. Both radical mediated thiol-ene “click” and amine catalysed Michael additions have been used in order to graft acrylates to the polymer surface, and the formation of disulphide bonds between the polymer surface and thiols has been explored.
The non-crosslinking monomer pentafluorophenyl acrylate (PFPA) has also been incorporated into thiol-acrylate polyHIPEs in order to provide a route to post-polymerization functionalization. The reaction between the PFPA within the polymer network and amines occurs under mild conditions and so this has been explored as a route to the incorporation of biomolecules in the polymer network
EXPRESSION, REGULATION AND RELEASE OF HUMAN PLACENTAL ANTIGENS: IMPLICATIONS FOR THE MATERNAL IMMUNE RESPONSE TO THE FETUS
Pregnancy represents a unique immunological arrangement where the maternal immune system must tolerate and support the genetically foreign fetus. The mechanisms by which maternal tolerance to the fetus is achieved and the consequences if this balance is disrupted are not completely understood. In this work, we have shown for the first time that the placenta expresses at least six known human minor histocompatibility antigens (mHAgs), including three autosomal antigens, HA-1, BCL2A1 and KIAA0020, and three Y-chromosome-encoded antigens, DDX3Y, RPS4Y1 and KDM5D. In addition, we have shown that expression of at least one of these antigens, HA-1, is decreased in term as compared to first trimester placentas (P<0.01), is regulated by oxygen and is significantly higher in pre-eclamptic placentas as compared to controls (P=0.015). We also examined the protein content of exosomes released from the outermost layer of the placenta (trophoblast-derived exosomes) using mass spectrometry and found that, in addition to several exosome markers, trophoblast-derived exosomes contain the immune molecule HLA-DR, which is not expressed on the surface of the trophoblast. We then treated dendritic cells with trophoblast-derived exosomes either in the presence or absence of the immunostimulatory molecule, LPS. Dendritic cells treated with exosomes alone showed significant increases in IL-8 (P=0.05), VCAM-1 (P=0.01) and CD80 (P=0.05) mRNAs whereas dendritic cells treated with LPS + exosomes showed a significant decrease in CCL7 (P=0.03) and CD40LG (P=0.002) when compared to controls. In conclusion, we have found that the placenta expresses at least six mHAgs, that expression of at least one of these mHAgs, HA-1, is regulated by oxygen and is increased in placentas from women with pre-eclampsia, and that that exosomes released from placental trophoblast cells contain at least one known fetal antigen, HLA-DR, and can alter dendritic cell phenotype. Taken together, these findings indicate that the placenta expresses and releases antigenic materials into the maternal blood stream and may affect maternal immune responses to the fetus during pregnancy. These findings may have important implications for the maintenance of a healthy pregnancy, numerous pregnancy complications and many other diseases involving immune responses to foreign and self-antigens
Comparison of different proteases and direct cell lysis methods used for the recovery of exogenous DNA from fingernail evidence
Fingernail samples are analyzed in forensic casework to determine the source of the nail and/or to recover a foreign profile from beneath the nail. When extracting from a fingernail sample, it is possible to recover deoxyribonucleic acid (DNA) of the nail donor from within the nail and from the surface of the nail; similarly, foreign DNA may also be present on and recovered from the nail surface. When attempting to recover the latter, fingernail samples present particular problems. Often, the foreign component is masked by the greater mass of donor DNA present within and on the nail sample. This masking effect is exacerbated by the use of proteinase K (PK) in DNA extractions, as PK, with an average of 200 cut sites per keratin molecule, is capable of breaking open the keratin matrix of the nail and exposing the nail DNA intercalated in the matrix. Directly extracting nail clippings, in contrast to swabbing or scraping, would further introduce nail DNA when using proteinase K. The present study explores whether utilizing other proteases (ZyGEM, Acrosolv, and Factor Xa) with fewer cut sites than PK or direct lysis methods (IGEPAL® CA-630 and MAWI iSWABTM-ID) would minimize recovery of nail
DNA from within the nail and thus mitigate the masking effect often seen with fingernail samples.
The endogenous DNA extraction efficiency of each suggested method was compared with the manufacturer’s standard QIAGEN QIAamp® DNA Investigator extraction protocol for hand-washed and/or laboratory-cleaned nails. The extraction results from the hand-washed nails demonstrate variability both within samples from the same donor and between donors. In contrast to previously published literature, a comparison of the results between the hand-washed and cleaned nails suggests that much of the endogenous DNA recovered from fingernail samples is derived from DNA on the surface rather than from within the nail.
QIAamp® extraction with the inclusion of dithiothreitol (DTT) recovered significantly more DNA (0.845 ± 0.651 nanograms of DNA per milligram of nail [ng DNA/mg nail]; p = 0.0045) than the same protocol without DTT (0.278 ± 0.253 ng DNA/mg nail). IGEPAL® recovered the least endogenous DNA (0.005 ± 0.012 ng DNA/mg nail) from the nail. The ZyGEM extraction recovered the second lowest amount (0.163 ± 0.161 ng DNA/mg nail) and both the Acrosolv (0.546 ± 0.607 ng DNA/mg nail) and MAWI’s iSWABTM-ID (0.681 ± 0.780 ng DNA/mg nail) methods recovered more DNA than the QIAamp® protocol without DTT. An assessment of the electropherograms resulting from cleaned fingernails across all extraction methods for one donor showed that both IGEPAL® and MAWI failed to recover a complete profile, whereas the remaining methods were able to recover complete profiles of the nail donor.
An assessment of donor variability found variations in terms of endogenous nail DNA recovery.
Fingernails were also spiked with blood, saliva, or semen to assess the recovery of foreign DNA. The extractions of the spiked nail samples demonstrate variability across all samples, owing, to some degree, to inconsistencies of sample preparation. IGEPAL®’s inability to recover complete foreign profiles suggests that the method may not be viable for extraction of fingernail samples. Conversely, the ZyGEM, Acrosolv, and MAWI extraction methods demonstrate potential as alternative extraction methods for fingernail samples and would benefit from additional experimentation
Borderline Contradictions
Borderline contradictions have long been considered to be false, but recent
developments in the intersection of the elds of experimental philosophy
and linguistics have lead to a consensus that ordinary speakers of natural language
nd borderline contradictions to be true. Furthermore, speakers are
more likely to agree to disjunctive borderline contradictions (:(A _ :A))
than their conjunctive counterparts (A ^ :A). We focus our attention on
a series of studies of this inequality, culminating in Egr e and Zehr's 2016
algorithmic account, which invokes strict and tolerant operators to predict
that while speakers are more likely to agree to disjunctive contradictions than
to conjunctive contradictions, they are also more likely to agree to both of
these than to their positive and negative subparts (A and :A). We present
the results of three new studies, one a replication of Egr e and Zehr's work,
the results of which suggest that speakers only nd the positive subsentence
to be false, suggesting that some leading accounts of how speakers interpret
borderline contradictions may require modi cation
Recommended from our members
Identification and PTSD Screening of Military Veteran Patients in Community Healthcare: A Quality Improvement Project
Background: Military veterans are at an increased risk for post-traumatic stress disorder (PTSD) related to their prior military service. Establishing veteran status of patients cared for in civilian healthcare and screening for PTSD will increase the likelihood of identifying symptoms and prompt appropriate treatment. Purpose: The focus of this project is to increase practitioner awareness and knowledge of PTSD in veteran patients as well as to identify and screen veteran patients for PTSD symptoms utilizing the primary care PTSD screen (PC-PTSD). Method: To determine veteran status, patients over the age of 18 years in an internal medicine clinic will be asked during their appointment check-in if they have ever served in the military. Identified veteran patients will be handed a questionnaire with the PC-PTSD screen to fill out and bring into their exam. Analysis and discussion of the PC-PTSD results by providers will reveal risk for PTSD and identify if further treatment or intervention is warranted. Results: Fifteen providers and staff attended the education presentation and eight completed the pre/post-presentation questionnaire. Post-presentation, the questionnaires revealed an increase in knowledge from 90% to 100%. After the intervention was completed, 34 veterans were identified from the total 1434 patients seen during the 30-day implementation timeframe, with one veteran screening positive for PTSD. This reveals 1-2 veteran patients are coming to the clinic per day. Clinical Implication: Identifying patient veteran status will reveal PTSD symptomology that may have otherwise gone unrecognized or overlooked. Identifying even one veteran suffering from PTSD can lead to positive patient outcomes. A sustainable systemic approach to identifying and screening veterans for PTSD in civilian primary care is necessary to thoroughly and holistically care for this vulnerable population
Using panel data to estimate the returns to schooling in South Africa
Includes bibliographical referencesReturns to schooling have typically been estimated with cross-sectional data. However, these studies are fraught with difficulties arising from the endogeneity of education. Individual effects that cannot be measured, such as ability and family background, cause bias in the estimates because they are correlated with education. A panel data approach is thus potentially superior to a cross-sectional one, in that it allows the individual effects to be eliminated with time-differencing. However, time-invariant regressors, such as education, cannot be identified under these time-differencing techniques. This paper therefore uses a Generalized Instrumental Variables method that was developed by Hausman and Taylor (1981) to estimate returns to schooling under a panel data context. This approach both controls for endogeneity bias and allows the identification of time-constant regressors, in this case, education. The re- turns to schooling under this estimation method are approximately 21% for South African individuals who are consistently employed from 2008-2013
Spine Lifting Biomechanics Between Varying Occupational Activity Levels And Recreational Physical Activity Levels
Background: Moderate to vigorous physical activity as the optimum movement patterns for health have continued to be the dominant focus of health and fitness research. Yet, emerging evidence of deleterious, adverse health effects of prolonged inactivity, independent of regular physical activity, presents a new element to establishing the ideal model of movement patterns for health. The musculoskeletal trunk of the body becomes unbalanced as a result of prolonged inactivity, and a biomechanical analysis can help to identify high-risk loading behavior associated with these unbalances. Moreover, poor spine biomechanics can indicate a need for adjustment to present recommendations for optimum movement patterns. Some research of spine biomechanics associated with sedentary occupation or lifestyle exists. However, up to the author’s knowledge, no research exists on sedentary lifestyle independent of recreational physical fitness in respect to spine biomechanics. Purpose: The purpose of this study was to identify biomechanical patterns and significant differences in lifting biomechanics among individuals who are occupationally inactive and active, as well as recreationally active and inactive. Methods: Participants were divided into four groups using the Cambridge EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk Physical Activity Questionnaire (EPAQ2): inactive, moderately inactive, moderately active, and active. A total of 23 participants completed the protocol. Spine kinematics of lifting was collected through VICON motion capture system. Additionally, ground reaction forces (GRF) and ground reaction moments (GRM) were collected by forceplate. Kinematic dependent variables were calculated from joint angle curves of trunk segments; included was maximum angular displacement of the middle trunk and lower trunk. Kinetic dependent variables were calculated from the GRF and GRM data, including maximum anterior excursion, maximum anterior velocity, and sway area of the center of pressure (COP) trajectories. Difference of each dependent variable between groups was detected by 1-way ANOVA. When difference existed, post-hoc pair-wise comparisons were conducted and Bonferroni correction was applied to minimize family-wise errors. The significance level was set at α = 0.05. Hypothesis: Participants who maintain an inactive lifestyle, regardless of recreational physical activity, will exhibit significantly different lifting biomechanics when compared to the lifting biomechanics of an active population performing the same lifting tasks. Results: Results indicated a statistically significant difference in flexion range of motion for the inactive group compared to all other groups (p=0.014). The inactive group had a significantly lower degree of flexion range of motion. Joint kinematic data indicated little difference between groups for the reaching phase and lift up phase of straight leg lifts. For bent leg lifts, the active population had significantly greater middle trunk flexion displacement during the reaching phase (p=0.005) and lifting phase (p=0.023) of bent leg lifts. No other significant differences existed between the other groups. Analysis of force platform data produced no significant differences between groups. Percent flexion range of motion was significantly different for the active population during the bent leg reaching phase and lifting phase compared with all other groups. The active population used a much larger degree of their total flexion range of motion to reach and lift up the box from the ground. Discussion: The current study aimed to investigate the effect of a largely inactive lifestyle, independent of regular participation in planned physical exercise, on spine kinematics, center of pressure, and range of motion. Results show evidence of a tendency for greater range of motion and greater flexion displacement of the active sample. Although not statistically significant, the inactive sample findings unexpectedly indicated a tendency for increased flexion displacement compared with the moderately active and moderately inactive groups. The moderately inactive group did not have any significant differences when compare to the moderately active group, which did not support the original hypothesis. However, the inactive group had poorer range of motion compared with all other groups, which supports the initial predictions. In summary, the inactive group presented some evidence of poor biomechanics. The active group shosigns of increased range of motion and flexibility. Finally, the moderately active and moderately inactive groups were very similar among all calculated variables. These findings support previous evidence of regular activity improving range of motion and flexibility. Occupational inactivity coupled with regular recreational activity appears to reduce the risk of developing poor lifting biomechanics
- …